Remove UNIQUENAME and LATEST_LINK.
UNIQUENAME was never unique, it was only used by USE_LDCONFIG and now,
we won't have conflicts there.
Use PKGBASE instead of LATEST_LINK in PKGLATESTFILE, the *only* consumer
is pkg-devel, and it works just fine without LATEST_LINK as pkg-devel
has the correct PKGNAME anyway.
Now that UNIQUENAME is gone, OPTIONSFILE is too. (it's been called
OPTIONS_FILE now.)
Reviewed by: antoine, bapt
Exp-run by: antoine
Sponsored by: Absolight
Differential Revision: https://reviews.freebsd.org/D3336

For some reason PKGNAMESUFFIX is not added to UNIQUENAME, so force it.
This fixes -client and -server both creating ${LDCONFIG_DIR}/mariadb,
as well as allowing different /var/db/ports/directories which is good
since -client and -server have different options.
It's probably not strictly necessary to apply this change to -scripts,
but do it anyway for consistency.